diff --git a/super-ddf.c b/super-ddf.c
index e98e411..2ec04a7 100644
--- a/super-ddf.c
+++ b/super-ddf.c
@@ -2178,7 +2178,7 @@ int validate_geometry_ddf_container(struct supertype *st,
 	}
 	close(fd);
 
-	*freesize = avail_size_ddf(st, ldsize);
+	*freesize = avail_size_ddf(st, ldsize >> 9);
 
 	return 1;
 }